| Calculate_weights {wcox} | R Documentation |
Calculate inverse probability of selection weights.
Description
This function calculates weights to correct for ascertainment bias in time-to-event data where clusters are outcome-dependently sampled, for example high-risk families in genetic epidemiological studies in cancer research.
Usage
Calculate_weights(dat)
Arguments
dat |
Data.frame with one row per individual with columns d non-censoring indicator; k interval of (age) group; S_k population interval-based proportion of individuals experiencing the event in intervals later than k; S_k. sample proportion of individuals experiencing the event in intervals later than k. |
Details
Weights are based on a comparison between the survival between sample and population. Therefore, besides the sample data, the population incidence rate (per 100 000) is needed as input, as well as the cut-offs of the (age/time-to-event) groups for which this is available. The function provides two options for the latter: cut-offs can be provided manually or using the standard 5- or 10-years (age) categories (0-4, 5-9, ... or 0-9, 10-14, ...). Note that resulting intervals are of the form [xx, xx).
Value
Vector with weights.